US6648999B2ExpiredUtilityA1

Low pressure laminated ceramic devices and method

63
Assignee: MOTOROLA INCPriority: Aug 27, 2001Filed: Aug 27, 2001Granted: Nov 18, 2003
Est. expiryAug 27, 2021(expired)· nominal 20-yr term from priority
Inventors:Jeremy BurdonRong-Fong Huang
C04B 2235/9615C04B 35/10C04B 2237/62C04B 2237/343B32B 2309/022C04B 35/638B32B 18/00C04B 2235/656C04B 35/63444C04B 35/632C04B 35/653C04B 2237/525B32B 37/04C04B 35/645C04B 2235/36
63
PatentIndex Score
6
Cited by
4
References
24
Claims

Abstract

An intermediate low-pressure laminated ceramic device is formed from a plurality of layers of unfired ceramic material each including ceramic particles in an organic binder. A polymer interfacial layer having a glass transition temperature such that it flows at a temperature below a temperature required for the unfired ceramic layers to substantially deform, is deposited on one surface of each of the unfired ceramic layers. The unfired ceramic layers are stacked with an interfacial layer positioned between adjacent unfired ceramic layers in the stack. The stack is heated to a temperature greater than the glass transition temperature of the interfacial layers and a pressure is applied to the heated stack below approximately 1200 psi to fixedly bond the plurality of layers in the stack together.

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
       1. A method of forming intermediate low-pressure laminated ceramic devices comprising the steps of: 
       providing a plurality of layers of unfired ceramic material each including ceramic particles in an organic binder;  
       depositing a polymer interfacial layer on one surface of each of the plurality of layers of unfired ceramic material, the polymer interfacial layer having a glass transition temperature such that the polymer interfacial layer flows at a temperature below a temperature required for the plurality of layers of unfired ceramic material to substantially deform;  
       stacking the plurality of layers of unfired ceramic material in overlying relationship to form a stack with a polymer interfacial layer positioned between adjacent unfired ceramic layers in the stack;  
       heating the stack to a temperature greater than the glass transition temperature of the polymer interfacial layer; and  
       applying a pressure to the heated stack below approximately 1200 psi to fixedly bond the plurality of layers in the stack together.  
     
     
       2. A method as claimed in  claim 1  wherein the step of depositing the polymer interfacial layer includes depositing the interfacial layer in the form of a polymer solution. 
     
     
       3. A method as claimed in  claim 2  wherein the step of depositing the interfacial layer in the form of a polymer solution includes depositing an aqueous solution of Poly(2-ethyl-2-oxazoline). 
     
     
       4. A method as claimed in  claim 3  wherein the step of depositing the aqueous solution of Poly(2-ethyl-2-oxazoline) includes depositing a coating less than approximately 1200 nm thick. 
     
     
       5. A method as claimed in  claim 4  wherein the step of depositing the aqueous Solution of Poly(2-ethyl-2-oxazoline) includes spraying the aqueous solution in droplets. 
     
     
       6. A method as claimed in  claim 4  wherein the step of depositing the aqueous solution of Poly(2-ethyl-2-oxazoline) includes adding a surfactant to the aqueous solution. 
     
     
       7. A method as claimed in  claim 6  wherein the step of adding the surfactant to the aqueous solution includes adding one of an ionic and a non-ionic surfactant in a concentration range of approximately 0.2 to approximately 2 wt % of polymer in the aqueous solution. 
     
     
       8. A method as claimed in  claim 1  wherein the step of depositing the polymer interfacial layer includes depositing the interfacial layer using a tape transfer process. 
     
     
       9. A method as claimed in  claim 8  wherein the step of depositing the interfacial layer using the tape transfer process includes depositing a layer of Poly(2-ethyl-2-oxazoline). 
     
     
       10. A method as claimed in  claim 9  wherein the step of depositing the layer of Poly(2-ethyl-2-oxazoline) includes the steps of providing a transfer tape including the layer of Poly(2-ethyl-2-oxazoline) and a backing layer, placing an exposed surface of the layer of Poly(2-ethyl-2-oxazoline) in contact with a surface of one of the layers of unfired ceramic material, applying pressure while heating to above 66° C., and removing the backing layer while leaving the layer of Poly(2-ethyl-2-oxazoline) attached to the surface of the one of the layers of unfired ceramic material. 
     
     
       11. A method as claimed in  claim 1  wherein the step of depositing the polymer interfacial layer includes depositing the interfacial layer in a molten state. 
     
     
       12. A method as claimed in  claim 1  wherein the step of depositing the polymer interfacial layer includes depositing the interfacial layer using hot-melt processing. 
     
     
       13. A method as claimed in  claim 12  wherein the step of depositing the polymer interfacial layer includes depositing the interfacial layer using a hot-melt gap-coat process. 
     
     
       14. A method as claimed in  claim 12  wherein the step of depositing the polymer interfacial layer includes depositing the interfacial layer using a hot-melt slot-die process. 
     
     
       15. A method as claimed in  claim 12  wherein the step of depositing the polymer interfacial layer includes depositing the interfacial layer using a hot-melt reverse gravure-coat process. 
     
     
       16. A method as claimed in  claim 1  wherein the step of heating the stack includes heating the stack to a temperature in a range of approximately 50° C. to approximately 80° C. 
     
     
       17. A method as claimed in  claim 16  wherein the step of applying the pressure to the heated stack includes applying a pressure in a range of approximately 500 psi to approximately 1200 psi. 
     
     
       18. A method as claimed in  claim 1  wherein the step of applying the pressure to the heated stack to fixedly bond the plurality of layers in the stack together includes applying sufficient pressure to produce hydrogen-bonding between the organic binder in the plurality of layers and the polymer interfacial layer. 
     
     
       19. A method of forming low-pressure laminated intermediate ceramic devices comprising the steps of: 
       providing a plurality of layers of unfired ceramic material each including ceramic particles in an organic binder;  
       depositing a polymer interfacial layer on one surface of each of the plurality of layers of unfired ceramic material, the polymer interfacial layer including an aqueous solution of Poly(2-ethyl-2-oxazoline) having a glass transition temperature in a range of approximately 50° C. to approximately 80° C.;  
       stacking the plurality of layers of unfired ceramic material in overlying relationship to form a stack with a polymer interfacial layer positioned between adjacent unfired ceramic layers in the stack;  
       heating the stack to a temperature greater than the glass transition temperature of the polymer interfacial layer; and  
       applying a pressure to the heated stack in a range of approximately 500 psi to approximately 1200 psi to fixedly bond the plurality of layers in the stack together.  
     
     
       20. A method as claimed in  claim 19  wherein the step of applying the pressure to the heated stack to fixedly bond the plurality of layers in the stack together includes applying sufficient pressure to produce hydrogen-bonding between the organic binder in the plurality of layers and the polymer interfacial layer. 
     
     
       21. A method as claimed in  claim 19  wherein the step of depositing the aqueous solution of Poly(2-ethyl-2-oxazoline) includes depositing a coating less than approximately 1200 nm thick. 
     
     
       22. A method as claimed in  claim 21  wherein the step of depositing the aqueous solution of Poly(2-ethyl-2-oxazoline) includes spraying the aqueous solution in droplets. 
     
     
       23. A method as claimed in  claim 22  wherein the step of depositing the aqueous solution of Poly(2-ethyl-2-oxazoline) includes adding a surfactant to the aqueous solution. 
     
     
       24. A method as claimed in  claim 23  wherein the step of adding the surfactant to the aqueous solution includes adding one of an ionic and a non-ionic surfactant in a concentration range of approximately 0.2 to approximately 2 wt % of polymer in the aqueous solution.

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